研究のタイプ: 医学／生物学の研究 (experimental study)

[覚醒時のパルス状高周波電磁界へのばく露はヒトのEEGに影響する] med./bio.

Exposure to pulsed high-frequency electromagnetic field during waking affects human sleep EEG

著者: Huber R, Graf T, Cote KA, Wittmann L, Gallmann E, Matter D, Schuderer J, Kuster N, Borbely AA, Achermann P
掲載誌: NeuroReport 2000; 11 (15): 3321-3325
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この研究は、デジタル無線電話ハンドセットから放射される電磁界（EMF）が、脳の生理機能に影響を与えるか否かをボランティア実験で調べた。健康な若年男性被験者をばく露群と擬似ばく露群に分け、睡眠前の覚醒期に30分間のEMF（900 MHz;空間ピーク比吸収率1 W / kg）ばく露または擬似ばく露を与えた。その結果、擬似ばく露群と比較して、ばく露群では、ノンレム睡眠期のEEGのスペクトルパワーが増加した；最大の増加は、睡眠開始期の9.75-11.25 Hz および12.5-13.25 Hz帯域で生じた；このような変化は、先行研究（睡眠中にEMFを断続的ばく露）で得られた変化と対応する；頭部片側へのばく露は、EEGのスペクトルパワーの半球非対称性を引き起こさなかった、と報告し、パルス高周波EMFによって誘発される脳機能の変化はばく露時間を超えて持続したと考察している。

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研究目的（著者による）

To investigate whether electromagnetic field emitted by digital cellular phones affects brain physiology.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900 MHz
Modulation type: pulsed
ばく露時間: continuous for 30 min
  • 電力: 2.2 W average over time (antenna input)
  • SAR: 1 W/kg maximum (10 g) (spatial peak)
  • SAR: 0.28 W/kg average over mass (brain) (±70%, exposed hemisphere)

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 30 min
Modulation
Modulation type pulsed
Duty cycle 87.5 %
Repetition frequency 217 Hz
Additional information

modulation as in the reference article simulating the main frames of the GSM system (2, 8, 217, 1736 Hz)
ばく露装置
ばく露の発生源／構造
  • planar antennas
Distance between exposed object and exposure source 11 cm
ばく露装置の詳細 Subjects were sitting on a chair with their heads between to plates to ensure a well-defined position with respect to two matched planar antennas mounted on both sides of the head at a distance of 11 cm from the ear with their centres 4.2 cm vertically above the ear canal.
Additional information The experiment consisted of three sessions one week apart involving right or left hemisphere and sham exposure scheduled according to a randomized, double-blind, cross-over design.
パラメータ
測定量 値 種別 Method Mass 備考
電力 2.2 W average over time - - antenna input
SAR 1 W/kg maximum 測定値および計算値 10 g spatial peak
SAR 0.28 W/kg average over mass 測定値および計算値 brain ±70%, exposed hemisphere
Additional parameter details

In order to achieve a relatively homogeneous exposure of the brain hemisphere, the ratio of averaged SAR values between the two hemispheres was only ~5.

測定および計算の詳細

Detailed dosimetric analysis was performed with the SEMCAD simulation platform based on the MRI data set of the head of a female subject aged 40. Numerical dosimetry was verified using the near-field scanning system DASY3 and a generic twin phantom filled with tissue simulating liquid, and the correspondence was better than 10%. Effects of the electrodes resulted in a reduction of the spatial peak SAR of ~10%. The uncertainty of the dosimetry was estimated to be less than ±30%.

Reference articles

ばく露を受けた生物:

方法 影響評価項目／測定パラメータ／方法

研究対象とした生物試料:
研究対象とした臓器系:
調査の時期:
  • ばく露後

研究の主なアウトカム（著者による）

Compared with the sham exposure, spectral power of the EEG in non-rapid eye movement sleep (REM sleep) was increased. The maximum rise occured in the 9.75-13.25 Hz band during the initial part of sleep. Unilateral radiation induced no hemispheric asymmetry of EEG power. The data show that exposure during waking modifies the EEG during subsequent sleep. Thus the changes of brain function induced by pulsed high-frequency electromagnetic fields outlast the radiation period.

研究の種別:

研究助成

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